FXUS65 KBOU 241810 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1210 PM MDT Fri Apr 24 2026 .KEY MESSAGES... - Elevated to Critical fire weather conditions redevelop today. - Cold front arrives this evening with cooler weather for Saturday, and improving precipitation chances by Sunday. - Unsettled and cooler weather pattern for a change sticks around for much of the upcoming week. No big storm expected to relieve the drought (<20% chance), but a few bouts of light rain expected. && .DISCUSSION /Through Thursday/... Issued at 1105 PM MDT Thu Apr 23 2026 A weak surge or two backing into northeast Colorado through early Friday morning is expected to wash out by afternoon, with warmer and drier conditions developing. It's uncertain as to if we'll fully mix and warm to our full potential (lower to mid 70s), however, given lack of lee troughing. That may also have some implications for fire weather...see Fire Weather Discussion section below. It will remain dry with no precipitation expected outside of an isolated light shower/flurry over the northern mountains Friday afternoon/evening. A cold front arrives Friday evening with a blast of north winds gusting to 30-40 mph. However, that initiates a much needed turn of events for the forecast area. The weather pattern will be undergoing a shift this weekend, to one characterized by cooler and showery weather as a series of upper level disturbances moves across the area through the week ahead. However, none of these appear to be particularly strong, so we'll have to rely on a moistening airmass along with synoptic scale forcing and bouts of upslope for most of our precipitation chances. The first of these chances will start late Saturday and Saturday night as weak forcing arrives in advance of a deeper trough for Sunday. We'll see the highest chance of precipitation wait until Sunday afternoon and evening and the main upper level trough ejects northeast across the forecast area. There is modest QG forcing and precipitable water (PW) values climbing to around 150% of normal. However, there is some uncertainty as to whether we retain a shallow upslope component or if we end up downsloping again too much as the main disturbance passes overhead. As a result, we don't see this as being a persistent rain event and overall precipitation amounts will be on the lighter side. ENS 24 hour precipitation means for this first round are less than 0.25" for the I-25 Corridor and adjacent plains, and near 0.50 for the far northeast plains and Park Range in the mountains, while the typically wetter GEFS has slightly higher means - but mostly because about a third of the GEFS still maintained QPF > 0.50 inch along the I-25 Corridor. Given this year and the still dry pre-trough environment, we'll have more confidence in the lighter precipitation amounts. We should still get a few inches of snow over the mountains with some minor travel impacts at times over the higher passes. A lot more uncertainty enters the picture by Monday as model cores and ensembles diverge somewhat on possible solutions. While there's high confidence we stay troughy, there is lower confidence regarding specific timing of the embedded shortwaves and higher precipitation chances. It is more certain we'll stay on the poleward side of the jet, and thus have deeper moisture and instability to work with. It's possible we see a trailing shortwave bring an enhanced batch of showers for later Monday into Monday night or even Tuesday, but again this is difficult to time. We'll probably see a break of a day or two, before the next system arrives later in the week (at least according to the ensemble averages). This one, for now, has a 50-60% chance of providing modest precipitation amounts of >0.50 inch, but just a slight chance (20%) of a more significant precipitation event with that one. We'll just keep daily chance of showers and cooler temperatures in the forecast. There is still potential for above normal temperatures in the middle of the week if we see a drier day or two develop in between. && .AVIATION /18Z TAFS through 18Z Saturday/... Issued at 1146 AM MDT Fri Apr 24 2026 Winds will be a bit all over the place for the next couple of hours. We have a boundary or two out there right now that are causing variable gusty winds. Winds are generally switching between SE and SW, with gusts around 15 to 20kts. Winds will start turning clockwise over the next couple of hours. We could see periods of lights winds and gusts around 20kts during this time. Winds at DIA have quite a bit of uncertainty this afternoon. The boundaries and surface troughing will lead to a difficult forecast for DIA. Right now, we have gusty winds from the NW later this afternoon before winds turn more westerly around 22Z or 23Z. However, there is a low chance that we could see winds swing all the way around to the NE around 21Z instead. The gusty W winds should prevail late this afternoon into the early evening before winds start to weaken a bit. A strong front is expected to move through the terminals between 3Z and 4Z this evening. Gusty NE winds are expected along and behind the front for a few hours. Gusts around 25 to 35kts are expected. Behind the front, we're also expecting low ceilings, with CIGs dropping near 2000ft around midnight and continuing into the early morning. CIGs will start to lift and scatter out around 12Z to 14Z, while winds turn more easterly. && .FIRE WEATHER... Issued at 1105 PM MDT Thu Apr 23 2026 Elevated to critical fire weather conditions are expected to return on Friday. The main question regarding widespread critical conditions will be the winds, as there is some uncertainty in the eastern extent of the stronger gusts. Moderately strong upper- level westerly flow will be in place but winds in the low levels are weak (<20kt), limiting momentum transfer potential even with a relatively deep mixed layer. Also, a lee trough will develop but hug the foothills. As a result, a pocket of lighter winds may very well hold from around Denver to the northeast. The foothills and Cheyenne Ridge will have a better chance of seeing gusty winds due to stronger mixing and westerly flow...enough to support Red Flag conditions with marginal wind gusts of 25-30 mph. A cold front will push across the northeast plains by mid evening, with a sharp wind shift from the north. Then much improved fire weather conditions can be expected through much of the week ahead. && .BOU WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 8 PM MDT this evening for COZ214>216- 238>247-249. && $$ DISCUSSION...20 AVIATION...AP FIRE WEATHER...20